Can you bring a chair & sit outside on the lawn or patio & listen to the concert?

Yes you can, as long as you are out of the walkways

There's spots of grass in front. Ive seen ppl bring blankets, food, and drinks. Behind the venue there seating around the library where ppl always hang out but it doesn't sound as good.

You can, but it's all cement. There are some areas around the campus were you can probably listen from too

Nobody does access control outside beyond the ticket gates. You can sit on a bench out front or bring your own folding chair.